Lumber-curing kiln.



E. D.. Smm/IN. LUIVIBER CUHING KILN.

APPLICATION FILED DEC. I4. I9I7.

192769979, Patented Aug. 27, IMS.

3 SHEETS-SHEEI l.

MEL lu Imam/coz E. D. SIDMAN.

- LUMBER. CUHING KILN.

APPLICATION FILED 056.14, |912.

3 SHEETS-SHEET 2.

E. D@ Smm/IAN,

I UNIBER ACUFIIIIIG KILN. APPLICATION FILED DEC. I4. I9I7- 1927"@9'79. Patented Aug. 27, 1918.

3 SHEETS-SHEEI 3.

Vllllllllnllllll lll ll llllllllll :EDWARD D. SIDMAN, OF LONDON, ONTARIO, CANADA.

LUMBER-CURING' KILN.

imams.

Specification of Letters Patent.

Patented Aug. 27, 1918.

Application led December 14, 1917. Serial No. 207,034.

To all whom t may concern.'

Be it known that I, EDWARD D. SIDMAN, a citizen of the United States of America, residing at London, in the Province of Ontario and Dominion of Canada, have invented certain new and useful Improvements in Lumber-Curing Kilns, of which the following is a specification, reference being had therein to the accompanying drawings.

My invention relates to kilns for curing or drying lumber, and the object of the invention is to secure a construction which insures an automatic circulation of air within the kiln, which concentrates the heat at the unloading end of the kiln, and which progressively decreases the humidity of the air within the kiln. Another object of the invention is to secure a construction which requires no excavation or pit below the ground line of the kiln, which may be constructed at a marked saving in first cost and which also operates :at a noticeable saving in cost. Still another object of the invention is to obtain a construction in which the eX- pansion is properly taken care of without the objectionable breaking of the fittings, in which better circulation of the heating medium is obtained, in which less pipe is required to raise the temperature to the desired degree, and in which no heavy. expensive headers or expansion pipes are necessary. Further objects ofthe invention will more fully hereinafter appear.

In the drawings,-

Figure l is a plan view, with the roof removed, of a kiln embodying my invention;

Fig. 2 is a sectional side elevation thereof;

Fig. 3 is a sectional view on the line 3 3 of Fig. 2;

Fig. 4 is a sectional end elevation;

Figs. 5 and 6 are details of the foul air and cold air flues, respectively; and

Figs. 7 and 8are details of the pipe connections respectively in the tempering and finishing compartments.

A represents the kiln, provided with the tempering room or compartment A and the finishing room or compartment A2, which rooms or compartments are separated by the bridge wall B and the rolling curtain B fitting within the channel B2. The kiln is provided with the doors B3 at opposite ends thereof, or the loading and unloading ends.

The tempering room or compartment A is provided with the miter heat radiating pipes or coils C and C on the opposite side walls thereof, connected by the pipe C2 located adjacent to the ceiling of the kiln. The supply pipe C3 leading from a heating medium source, preferably steam, at the low pressure of from 2 to 5 pounds (not shown) connects with the riser C4 leading to the pipes or coils C and the return pipe C5 leading preferably to a suction system (not shown) 'connects with the pipes or coils C. To control the admission of the heating medium to the heat-radiating pipes or coils,

the valve D is provided near the lower end -The valve E4 controls the admission of the spray, and its operating stem is arranged to be operable from outside the kiln. Preferably the connection between the spray pipes E and the pipe E, such as the swinging joint connection, is such that the spray pipes are adjustable in position to suit the varying conditions.

The finishing room or compartment A2 is` provided with the combined miter wall and ceiling heat radiating pipes or coils F, comprising the opposite side wall horizontallyextending pipes or coils lF and F2 and the ceiling pipes or coils F3 extending transversely of the kiln roof and from near the center thereof to near the side walls and then dropping down to connect with the wall pipes or coils. Theceiling pipes or coils are located at the unloading end of the finishing room or compartment to concentrate the, heat at this'point. The supply pipe G leading preferably from the same heating medium source for the tempering room or compartment pipes or coils is connected with the wall pipes or coils F2 by the swing L G and the return-pipe G2 preferably leading to the same suction system for the tempering room or compartment pipes or coils is connected with the wall pipes or coils F by another swing L G3. To control the admission of the heating medium to the combined miter wall the ceiling heat-radiating pipes or coils, the valve l-l is provided with its stem lul extending outside of the room or compartment. Connected in a suitable manner to the heat-radiating pipes or coils is the spray pipe l adapted to lie beneath the cars carrying the lumber and extending substantially centrally and longitudinally oil the nishing room or compartment and for nearly its total length, said pipe having the spray apertures l in its upper portion. ik suitable valve l2 operable from outside the room or compartment controls the admission ot the spray.

rlhe wall heat radiating pipes or coils ll" and F2 extend substantially horizontally and rest on hook plates J secured to the strips zl upon the side walls, the arrangement being such that the pipes or coils are held a substantial distance from the side Walls of the kiln to secure a good circulation of air thereabout. rlhe ceiling heat-radiating pipes or coils .F rest upon the supports l extending longitudinally ot the finishing room or compartment, in turn held in lposition by means ot the lag-screw hangers li secured in the joists forming part ot the kiln roof. rl`he ceiling and wall pipes or coils are arranged preferably so that they slope gradually from the center oi` the kiln down to the sides thereof and then lengthwise to the return-pipe.

For the purpose ot ventilation in the linishing room or compartment a series ot foul air tlues L in one ot the side walls and a series of cold air tlues M in the other ot the side walls are employed. The foul air lines start at or near the ground line of the kiln and extend above the highest point of the root preferably one or more feet, said ilues being capped or surmounted by the vent head L for positively preventing a down draft being created in the lines. Each foul air flue is provided With the vertical opening lf therein approximately level with the bottom line of tne lumber piled on the standard car, the bottom of the opening being approximately eight inches above the rails carrying the cars, to be described presently. The openings L2 are controlled by sliding dampers L3,'preterably of the same size and formed or copper, these being dampers adapted to slide in groved guides secured to the side walls of the room or compartment. 'lhese sliding dempers are connected to the rod Z extending longitudinally of the linishing room or compartment and secured at one end to the lever Z pivoted at Z2, at the unloading end of the kiln, the lever Z being arranged to be easily reached by the arm of the operator trom outside the kiln.

To automatically graduate the amount or' humidity removedl from the ln'ln jrrom a minimum nearothe bridge wall to a mairimum near the unloading end as the lumber progresses through the finishing room or nasser/o,

compartment, the foul air openings lf are gradually increased in size from the opening nearest to the bridge Wall to the opening nearest to the unloading end.

rllhe cold air llues li/l start at or near the ground line of the kiln and extend to the ceiling line where they are tightly blocked od. Each of these lues is respectively provided adjacent to the ceiling and adjacent to the ground line With the horizontal openings li/l and M2, the size of the respective openings remaining substantially constant. To assist the foul air tiues to properly operate and to avoid the tendency of the heated air to escape through the cold air openings, the cold air lues are constructed to maintain a leg of cold air near the bottoni ot the lines by connecting with the outside air when in operation, the connections being controlled by an airtight damper (not shown), and by being heated by the side wall heat-radiating pipes or coils F and F2. This, with the natural suction produced by the foul air lines, prevents the current of air in the cold air liues from reversing. Another method ot maintaining a leg of cold air is to provide the cold air tlues with the tapped openings M3 outside of the kiln at any point from the ground line up to one third approximately ot the length ot the iiue below the ceiling, the openings being controlled by the dampers Mt sliding in the guides Due to the construction as thus far described, it will be seen that the circulation ot air Within the kiln is produced by the upward draft in the foul air lues and that this draft is not induced by auxiliary means within the lues but by the arrangement of the tlues in the side walls and the Wall heatradiating pipes adjacent thereto. rlhe maintaining of the leg ot cold air in the cold air dues further assists in the proper circulation. Better circulation is also obtained by having the foul air flue opening into the kiln at approximately the level ot the lower surtace of the lumber to be cured or dried. Further, the amount of heat-radiating pipes or coils is materially reduced.

To secure the best results, the combined area of the foul air i'iue openings into the kiln is such that with the velocity of air at approximately Q10 feet per minute a complete change of the kiln atmosphere takes place every hour. Air should also enter the cold air lues at approximately the same rate oft velocity.

rl`he rails N are employed for carrying the lumber-carrying cars and have a pitch of approximately l to l0 from the loading to the unloading ends of the kiln. rllhe rails are secured to the iron pipe and track sunports bl, the bottom flanges of which are fastened to the tops of the piers N2, preferably formed oit cement. Cross supporting pipes N8 properly secured to the pipe and track supports brace the same to make a substantial underwork.

In operation, assuming that the lumber to be cured or dried is 2 oak, which has been air-dried at least four months, the car carrying the same properly piled is pushed into the tempering room and the doors at the loading end and the rolling curtain are closed. The valve on the spray pipe is opened from one to ve minutes or until a thick gray fog or vapor inside the room or compartment is obtained, when the valve is closed until it admits just enough steam so that the heat from the spray alone will raise the temperature to 120 F. in not less than twelve hours. When this point is reached the valve controlling the heat-radiating pipes or coils is opened Wide to obtain a temperature of 165 F. to 17 5 F., care being taken to maintain the relative per cent. of humidity. For this purpose a hygrometer is used in which the wet and dry bulbs should read the same, and in no case should there be allowed a difference of over 5. This condition is maintained twenty-four hours from the time spray is first turned on, and then the lumber is ready to push into the finishing room or compartment, when the tempering room or compartment may be used again.

The car is then pushed into the finishing room or compartment just far enough to clear the curtain, and then the curtain is closed, as are also the doors at the unloading end and all the dampers to the ventilating system. The steam to the heat-radiating pipes or coils is turned on full, and when the temperature in the finishing room, or compartment reached 100 F., or over, the foul air flue dampers are partly opened. In thirty minutes or so, if the heat in lthe room or compartment continues to rise, the foul air flue dampers are opened wide and approXimately thirty minutes after this the cold air flue dampers are opened. The temperature within the finishing room or compartment is allowed to rise to 165 F. to 175 F., which is approximately thehigh limit with the present radiation and steam pressure, land when this point is reached the valve on the spray pipe is opened to admit the spray until the wet bulb on the hygrometer shows from 25 to 30 'lower than ythe dry bulb. Usually after the iinishing tempered it is pushed into the finishing room or compartment. When ten cars have been tempered the first car 1s cured or dried,

.if the operations have been carefully followed out.

Although I have shown my invention as applied to a multiple compartment or progressive kiln, it is to vbe understood that the same may be successfully applied to a single compartment or boX kiln. j

What I claim as my invention is 1. In a kiln for drying lumber, the combination with a room or compartment, of combined miter wall and ceiling heat-radiating pipes or coils for heating the interior thereof.

2. In a kiln for drying lumber, the combination with a room or compartment, of combined wall and ceiling heat-radiating pipes or coils for heating the interior thereof, and a spray pipe adapted to lie below the lumber to be cured or dried.

3. In a kiln for drying lumber, the combination with combined wall and ceiling heat-radiating pipes or coils for heating the interior of the kiln, of a spray pipe adapted to lie below the lumiber to be cured or dried, and valves controlling said pipes or coils lspild spray pipe, operable from outside the 11. In a kiln for drying lumber, the combination with combined wall and 'ceiling heat-radiating pipes or coils for heating the interior of the kiln, of a spray pipe adjustably connected with said pipes or coils, and

control means for said pipes or coils and spray pipe, operable from outside the kiln.

5. In a kiln for drying lumber, the combination with a series of wall heat-radiating pipes or coils, of a series of ceiling heatradiating pipes or coils, one of said series being located adjacent to one end of the kiln, the other series extending substantially the entire length thereof.

6. In a kiln for drying lumber, the combinationv with wall heating radiating pipes or coils extending substantially the length of the kiln, of ceiling heat-radiating pipes lqrl coils located adjacent to one end of the 7. In a kiln for drying lumber, the combination with wall heat-radiating pipes or coils, of ceiling heat-radiating pipes or coils, the greater proportion of the pipes or coils being located adjacent to the unloading end ofthe kiln.

8. In a kiln for drying lumber, the combination with a foul air iue in a wall thereof, of wall heat-radiating pipes or coils adjacent to said Wall for heating the interior ofthe kiln and inducing a draft in said flue, a portion of said' radiating pipes or coils being above the opening fromthe kiln into said foul air fiue.

9. In a kiln for drying lumber, the combination with a foul air flue in a side Wall thereof, provided with an opening into the kiln substantially level with the lower side of the lumber being cured or dried, and heatradiating means within the kiln for heating the interior thereof and inducing a draft in said flue.

10. ln a kiln for drying lumber, the combination with a room or compartment, of a series of foul air flues in one of the side Walls thereof, and means for automatically varying the amount of humidity removed from the room or compartment from a minimum near one end to a maximum near the opposite end.

11. ln a kiln for drying lmnber, the combination with a room or compartment, of a series of foul air dues in one of the side walls thereof, provided with openings into said room or compartment of graduallv increasing size from near one end thereof to the opposite end.

12. ln a kiln for drying lumber, a room or compartment, heating means for the interior thereof, arranged to give greater heat adjacent to one end thereof, and means for automatically varying the amount of humidity removed from said room or compartment from a maximum at the end 'Where the heating means is concentrated to a. minimum at the opposite end.

13. ln a kiln, the combination With a series of foul air lues in one of the side Walls thereof having openings into said kiln of varying size, of a series of cold air ilues in the opposite side Wall, viali heat-radiating pipes or coils upon the side Walls, and means for maintaining a column of cold air in said cold air flues near the bottom thereof.

1A. ln, a kiln, a room or compartment, a cold air flue in one of the side Walls of said room or compartment, and means for maintaining a column of cold air in said flue near the bottom thereof.

15. ln a kiln, the combination With a tem pering room having Wall heatradiating pipes or coils and a spray pipe, and valves controlling said pipes or coils and spray pipe from Without said room, of a finishing room, having combined Wall and ceiling heatradiating pipes or coils and a spray pipe, and valves controlling saidlast-mentioned pipes or coils and spray pipe, operable from Without the finishing room.

16. ln'a kiln, for drying lumber, a room or compartment, Wall-heating radiating pipes or, coils upon the side Walls thereof, a supply pipe, a return pipe, and swinging tjs connecting said pipes or coils to said supply and return pipes to allow of expansion thereof.

17. ln kiln for drying lumber, combined ceiling and miter wall heat-radiating pipes or coils for heating the interior of the kiln and the lumber contained taerein, a perforated spray pipe for admitting` moisture to the atmosphere Within the kiln, and an air flue extending from near the ground line of the kiln to a point above the highest point of the roof, and a non-down draft vent head capping or surmounting said flue.

1S. ln a kiln for drying lumber, the combination with heat-radiating pipes or coils for heating the interior of the kiln and the lumber contained therein, of a perforated spray pipe for admitting moisture to the kiln atmosphere, and a series of foul air lines in one of the side Walls of the kiln, each iiue being provided with an opening into the kiln and the combined area of the openings being such that with a velocity of air at approximately 210 feet per minute a complete change of the kiln atmosphere very hour will be made.

19'. ln a kiln for drying lumber, the combination with a series of foul air flues in a side Wall thereof, each provided with an opening into the kiln substantially level With the lower line of the lumber being cured or dried, dampers for covering said openings, a rod secured to said dampers, a lever adjacent to one end of the kiln and connected pivotally to said rod, and a common means for heating the interior of said kiln and inducing an rip-draft in said flues.

20, VThe process of curing or drying lumber, comprising the tempering of the lumber by successively spraying the same until a thick gray fog or vapor is obtained, raising the temperature by the spraying to approximately 120o F., raising the temperature by heating to from 165 to 1750 F., and maintaining meanwhile the same relative degree of humidity, and the inishing of the lumber by successively raising the temperature to 100O F., or over, opening the foul air and cold air ilues as the temperature raises to finally reach from 165 to 175 F., admitting moisture until the hygrometer Wet bulb shows from 25 to 30 lower than the hygrometer dry bulb, maintaining these temperatures and gradually decreasing the humidity.

2l. rThe process of curing or drying lumber, comprising the placing of the lumber in a tempering room in which the same is successively subjected to moisture for saturating and slightly heating the same and to greater heat, and the placing of the lumber in a finishing room in which the same is successively subjected to greater heat and progressive decrease of the humidity of the atmosphere relative to the unloading end of the kiln, the temperature remaining substantially constant.

22. The process of curing or drying lumber, comprising the placing of the same in a tempering room, the subjecting successively thereof to moisture from therebeneath to heat from near the sides thereof, l

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and the placing of the lumber into the finishing room, and the subjecting thereof t0 heat from near the sides and top thereof.

23. The process of curing or drying lumber, comprising the placing of the same into the tempering room, and the successive subjection thereof from therebeneath to moisture for saturating and slightly heating the same, and to greater heat from near the sides thereof, and the placing of the lumber into the finishing room, and the successive subjection thereof to greater heat from near the sides and top thereof, and to gradual decrease of the humidity While maintaining substantially the same temperature.

24. The process of curing or drying lumber, comprising the placing of the lumber in the tempering room, and successively subjecting the saine to saturation and loW heat from therebeneath and greater heat from near the sides thereof, and the placing of the lumber in the finishing room, and the successive subjecting of the same to greater heat from near the sides thereof to concentrated greater heat from near both the sides and top thereof, and meanwhile to the gradual decrease of the humidity in the kiln atmosphere.

In testimony whereof I aix my signature.

EDWARD D. SIDMAN. 

